1 April 2009

Is there a difference between naturally occurring sugars and refined sugar? We are often asked this. Not in GI terms. Naturally occurring sugars are those found in milk and other dairy products and fruits and vegetables, including their juices. Refined sugar means added sugar, table sugar, honey, maple syrup, or corn syrup. Both sources include varying amounts of sucrose, glucose, fructose and lactose. Some nutritionists make a distinction between them, because natural sugars are usually accompanied by micronutrients such as vitamin C.

The rate of digestion and absorption of naturally occurring sugars is no different, on average, from that of refined sugars. There is, however, wide variation within food groups, depending on the food. The GI of fruits varies, from 25 for grapefruit to 76 for watermelon. Similarly, among the foods containing refined sugar, some are low GI, some high. The GI of sweetened, low fat yoghurt is only 26 to 28, while a Mars Bar® has a GI of 62 (lower than bread).

Remember, a food’s GI alone doesn’t make it good or bad for you. The nutritional benefits of different foods are many and varied which is why we always suggest that you base your food choices on the overall nutritional content along with the amount of saturated fat, salt, fibre and of course, the GI value, which is why bread is a better option than a Mars Bar.

Why do dietitians and nutritionists recommend starchy foods over sugary foods? Sugar has an image problem that stems largely from research with rodents using unrealistic amounts of pure sugar. It’s also seen as a source of ‘empty kilojoules’ (energy without vitamins or minerals) and concentrated energy. But much of the criticism doesn’t stand up to actualresearch findings.

Most starchy foods have the same energy density as sugary foods and even a soft drink has the same kilojoule (calorie) content per gram as an apple. Starchy foods, such as wholegrain cereals can be excellent sources of vitamins, minerals and fibre, but some pure forms of starch and modified starches are added to foods that are ‘empty kilojoules’.

So there really isn’t a big difference between sugars and starches, either in nutritional terms or in terms of the glycemic index. Our advice is to use sugar to your advantage by adding it to nutritious foods (such as a little sugar on porridge or a smear of jam on low GI bread) to make them taste even better.